Electric lamp and similar devices



Patented Mar. 18, 1941 PATENT OFFICE ELECTRIC LAMP AND SIMILAR DEVICES Ernst-Gunther Andresen, Berlin, Germany, asaignor to General Electric Company, a corporation of New York Application November 6, 1939, Serial No. 303,150 In Germany October 20, 1938 2 Claims. (01.176-32) My invention relates to electric lamps and similar devices in which an electric energy translation element is sealed within an envelope. More patticularly, my invention relates to a combined 6 sealing body and base construction for electric lamps and similar devices, such as, for instance, tubular'gaseous discharge devices.

One object of my invention is to provide an improved seal for electric lamps and similar de- 10} vices which may be made very easily, occupies a minimum amount of space, and which permits an easy utilization of the lamp or device.

Another object of my invention is to provide a combined sealing body and base construction 15 for electric lamps and similar devices.

A feature of the invention is the use of a pressed glass disc as the sealing body for the lamp envelope, the disc being fused to the open end of the lamp envelope while resting flatly against such end.

According to the invention, two or more current leads are sealed into the pressed glass disc, and these leads terminate in two or more external contact pins the inner extremities of which 25 are embedded in the glass disc. The said leads support-one or several electrodes within thelamp in the case of an electric discharge device, or they support one or more filaments in the case 01' an electric incandescent lamp. The central portion of the glass disc, between the leading-in wires extending therethrough, is formed with an inwardly extending recessed projection which accommodates the lamp exhaust tube. In this manner, the tip or point of the exhaust tube is completely covered, or nearly so, and is disposed substantially within the recess in the pressed glass disc.

Further objects and advantages of my invenand from the accompanying drawing in which:

shown applied to an electric discharge device 50 comprising a tubular glass envelope I the ends of which are closed by means of a pressed glass disc 2 which is sealed by fusion to the said ends while lying flatly thereagainst. The envelope I may contain a filling of gas or v por or gas-vapor II mixtures. Two leading-in wires land are hertion will appear from the following description metically sealed or pressed into the glass disc 2 so as to extend therethrough into the envelope I, where they support an electric energy translation element 3 in the form-of a glow electrode, in the case of an electric discharge device, or in 5 the form of an incandescible filament in the case of an electric incandescent lamp. The outer ends of the leading-in wires 4, i terminate in contact pins 8, I the inner extremities of which are of conical shape and are likewise sealed or pressed into the pressed glass disc 2. To provide sufficient support for the leading-in wires 4, 5 andthe contact pins 8, 'I, .the disc 2 is formed with nipple-shaped inward projections 2', one leading-in wire extending through and being sealed into each projection. Between the two leading-in wires 4, 5 and preferably centrally thereof, the disc 2 is provided with an inwardly extending hollow projection 8 which is likewise formed during the molding process. This inward hollow projection provides a recess 8' for accommodating therein an exhaust tube 9 which is sealed to the inner end 01 the projection so as to provide a passageway communicating with the interior of the lamp envelope I. The exhaust tube, after the evacuation and the filling of the envelope with the desired gas filling, is tipped off at a point within the recess 8' or nearly so, as indicated at III in Fig. 1, so that the said tip is more or less covered or protected within the recess 8.

To prevent damage to the exhaust tube til I0, and also to protect the glass-to-metal seal between the contact pins 6, I and the glass disc 2 as well as the sealing edge between the said disc and the lamp envelope I, a flat cap ll of suitable material fits over the end of the lamp envelope and is secured thereto in any suitable manner, such as by cement II. This cap II, which is preferably made 0! sheet metal, or possibly of a suitableinsulating material such as synthetic resin, is provided with suitably shaped openings or holes I3, I4 in alinement with the contact pins 6 and I so that the latter may extend therethrough. Where the cap is made of metal, the openings I3, l4 should be large enough to prevent any possible contact of the pins 6 and I with the edges 01' the cap openings; otherwise a short circuit might occur. The cap II, in addition to protecting the end of the glass'envelope against damage, also serves to improve the appearance of the lamp.

If desired, a layer of insulating material I! may be provided between the pressed glass disc 2 and the cap II to thereby seat the cap more firmly 2 on the end of the envelope. This insulating layer I5 is tormedwith a central opening IE to accommodate the tip ill of the exhaust tube where the said tip protrudes slightly beyond the end of the envelope l, as in the case shown in Fig. l. 4

In the modification shown in Fig. 2, the tip In of the exhaust tube lies completely within the central recess 8' in the pressed glass disc 2. Instead of a cap ll fitting over the entire end of the lamp envelope i, only a small closure cap I1 is employed which fits over the exhaust tube tip only. This cap I1 is cemented into the central recess 8' in the glass disc 2 by means of cement 18. Obviously, it is entirely possible to secure the cap ll in place in a different manner, for

instance, by clamping. Like the cap ll shown in Fig. 1, the cap l1 may be made of any suitable material, that is to say, it may be made of suitable insulating material or of metal.

What I claim as new and desire to secure by Letters Patent 0! the United States is:

1. An electric device comprising an elongated glass envelope having an end thereof closed by a pressed glass disc fused to the said end of said envelope, leading-in wires extending through and fused directly to said glass disc and electrically connected to contact pins'projecting outwardly pressed glass disc fused from said glass disc, said contact pins having their inner extremities sealed into said glass disc, a centrally arranged hollow re-entrant projection on said glass disc extending into said envelope and providing a recess in the outer surface 01' said disc, an exhaust tube depending from the inner end of said projection and sealed off within said recess, and a cover member secured to said disc and covering at least the portion of said disc which is recessed.

2. An electric device comprising an elongated glass envelope having an end thereof closed by a to the said end of said envelope, leading-in wires hermetically sealed into said glass disc and electrically connected to contact pins projecting outwardly from said glass disc, said contact pins having their inner extremities sealed into said glass disc, a centrally arranged hollow projection on said glass disc extending into said envelope and providing a recess in the outer surface of said disc,

an exhaust tube depending from the inner end of said projection and sealed off within said recess, and a closure cap fitting into and covering said recess and secured to the walls thereof.

ERNsT-G'UNTHER. ANDRESEN. 

